A waterproof computer is usually designed for military or industrial purpose to be operated in severe environments. Therefore, it is necessary for all components of the waterproof computer to be repellent to water. All connections on the computer that are exposed to external environment must have a waterproof plug installed thereat to protect the connections from flooding of water.
FIG. 1 is a sectioned side view showing a conventional waterproof plug for a data port 10 provided on an outer surface of a portable computer. The conventional waterproof plug includes a sealing flange 22 for fitly plugging into the data port 10 via an access 11 thereof to bear against the inner wall surface 12 of the data port 10, so that a cover plate 21 located at an outer end of the sealing flange 22 is completely and closely attached to the outer surface of the portable computer surrounding the access 11 of the data port 10 to prevent water from entering into the data port 10.
For the above-structured waterproof plug to provide waterproof effect, the sealing flange 22 must be fully plugged into the data port 10 for the cover plate 21 to completely and tightly attach to the outer surface of the portable computer. In the case of using the portable computer outdoors in a heavy raining day, rainwater tends to accumulate at the upper part of the cover plate 21 and could not be timely drained. The accumulated rainwater would finally leak from the sealing flange 22 into the data port 10 to cause damage to the portable computer.